This study focuses on the role of early childhood inhibition in the development of pathological risk indicators in children of families with and without parental depression. Patterns of child behavior in the face of the unfamiliar (persons, places), such as behaviors expressing inhibited exploratory activity and social withdrawal, are observed at 2 to 3 years of age in semi-naturalistic but standard settings, which represent varied contexts of unfamiliarity. Analyses of these data revealed that six reliable dimensions of mother and child response styles could be empirically derived from our observation coding system. These dimensions meaningfully distinguish groups of children in our sample at this very young age. Comparisons across maternal diagnostic groups (nondepressed, major depressive, and bipolar) indicate that the single factor that distinguishes depressed and nondepressed mothers is labelled Anxious, Nonfacilitative Involvement of Mother with Child, with both the major and bipolar mothers displaying higher levels of intrusive, awkward and negative behavior (e.g., critical of child's behavior) than the nondepressed mothers. Children of the bipolar mothers, as contrasted to those of the major and nondepressed mothers, typically show the highest levels of exploratory activity and confident, animated stranger approach and engagement. As a group the children of the major mothers typically show more cautious, less active exploration and stranger engagement than children in both the bipolar and nondepressed maternal groups. Children and mothers of the major depressive group are most notably distinguished from the bipolar group on the factor, Social Withdrawal and Flat Affect.